Tag: the origin of cells and cell division

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Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzyme urease, first crystallised by Sumner was obtained from

  1. Human urine

  2. Canavalia

  3. Pancratium

  4. Thalictrum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Sumner crystallized an enzyme known as urease from human urine and reported that all enzymes are protein. It catalyzes the hydrolysis of urea into carbon dioxide and ammonia. John Howard Northrop and Wendell Meredith Stanley shared the noble prize with Sumner for their work on the enzyme.
Buchner in 1897, prepared a yeast extract and added sugar solution to it and observed the process of fermentation. 
So, the correct answer is option A.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Match and find the correct option.

           $I$             $II$
$(a)$ Transferases $(i)$ Epimerase
$(b)$ Hydrolases $(ii)$ Kinases
$(c)$ Lyases $(iii)$ Phosphatase
$(d)$ Isomerase $(iv)$ Fumarase
  1. $a - ii, b - iii, c - iv, d - i$
  2. $a - ii, b - iii, c - i, d - iv$
  3. $a - ii, b - i, c - iii, d - iv$
  4. $a - ii, b - iv, c - iii, d - i$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A kinase is an enzyme that catalyzes the transfer of phosphate groups.  It belongs to the family of transferase. 
Phosphatase enzyme catalyzes the hydrolysis of its substrate,  it is a subcategory of hydrolases. 
Fumarase enzyme belongs to the family of lyases,  specifically hydro lyases, which cleave carbon-oxygen bonds. 
Epimerases are isomerase enzymes that catalyze the inversion of compounds. So the correct answer is A. 
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which of the following is not corretly matched for the organism and its cell wall degrading enzyme ?

  1. Bacteria - Lysozyme

  2. Plant cells - Cellulase

  3. Algae - Methylase

  4. Fungi - Chitinase
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In algae, the cell wall is made up of cellulose degraded by cellulase enzyme. Bacteria have lysozyme, plants cells have cell wall degraded by cellulose and fungi have chitinase.

So, the correct answer is 'Algae - Methylase'.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Which class of enzyme catalyzes following reaction?
$\overset { X }{ \underset { C }{ | }  } \overset { Y }{ \underset { C\longrightarrow \quad X-Y+C=C }{ | }  } $

  1. Hydrolases

  2. Lyases

  3. Ligases

  4. Isomerases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrolases are biological enzymes that catalyze the hydrolysis of a chemical reaction. They usually divide larger molecules into two smaller molecules. It is a class containing more than 200 enzymes. Some common hydrolases are esterases, proteases, lipases etc.

So, the correct option is 'Hydrolases'.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Choose the type of enzyme involved in the following reaction.


$S - G + S' \longrightarrow S + S' - G$

  1. Dehydrogenase

  2. Transferase

  3. Hydrolase

  4. Lyase

  5. Isomerase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Based on the type of reaction catalyzed, the international union of biochemist have classified enzymes into six major classes- Oxidoreductase, Transferase, Hydrolase, Lyase, Ligase and Isomerase.
Transferase is the general name for the class of enzymes that enact the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor).

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

In which one of the following enzymes, is copper necessarily associated as an activator? 

  1. Carbonic anhydrase

  2. Tryptophanase

  3. Lactic dehydrogenase

  4. Tyrosinase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Tyrosinase is a copper-containing enzyme present in plant and animal tissues that catalyzes the production of melanin and other pigments from tyrosine by oxidation, as in the blackening of a peeled or sliced potato exposed to air. In animals it is found inside melanosomes which are synthesised in the skin melanocytes.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

The cytochromes are 

  1. Peroxidase

  2. Iron protoporphyrin

  3. Pyridine nucleotides

  4. Metal containing flavoproteins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cytochromes are iron-porphyrin or heme proteins discovered by MacCunn. Cytochromes are bound to inner mitochondrial membrane and are primarily responsible for the generation of ATP via mitochondrial electron transport system. Whereas all other cytochromes have iron only, the cytochrome a possesses both iron and copper. With iron it picks up electrons and through copper it hands over electrons to oxygen.